This invention relates to a vacuum cleaner having primary and secondary filters, and more specifically, to an improved filter assembly f or use as a secondary filter.
Vacuum cleaners operate by filtering dirty air that flows through a main housing between a vacuum cleaner inlet and outlet. One well-known type of vacuum cleaner uses a primary filter that incorporates a basin filled with liquid, preferably water. A separator driven by a motor separates the dirt particles from the air and deposits them into the water. Although such filter arrangements can be highly effective, inevitably the vacuum cleaner filter is unable to filter all the air and smaller particles of dirt escape through the outlet. To address this problem, a secondary filter has been incorporated to further filter the air. The secondary filter is arranged between the primary filter and the outlet to trap very small dirt particles. A pleated fibrous filter, such as a HEPA filter, has been used that permits only virtually dirt-free air to be expelled from the vacuum cleaner outlet.
It is difficult to provide the vacuum cleaner user convenient access to the secondary filter located within the main housing when changing the filter. Several components have been used as part of the filter assembly, and may be eliminated to reduce cost. The filter has not been located within the housing in such a manner that ensures proper placement and easy replacement of the filter. Furthermore, when the user replaces the filter one is confronted with a dirty filter that is messy and undesirable in appearance. Therefore, what is needed is a self-contained filter assembly having fewer components that is self-locating for easy replacement.